Salesforce too many soql queries 101 whle inserting bulk data. I need to check if the contact is all ready present or not before inserting a new conta [closed]

Question

 public static void ContactFromAccount(List<Account> NewAccountList){
    
    list<Contact> contactList = new list<contact>();
    
    
    for(Account a : NewAccountList){
        Account newAccount = [Select Id,Name,Phone From Account where ID = :a.id];
        
        
        list<contact> newContactList = [select Phone from Contact where Phone = :newAccount.Phone]; // to check if the contact is there or not.
        
        if(newAccount.Phone != Null && newContactList.size() == 0 ){
            Contact c = new Contact();
            c.AccountId = newAccount.ID;
            c.Phone = newAccount.phone;
            
            if( !newAccount.name.contains(' ')){
                c.LastName = newAccount.name;
            }
            else{
                list<string> names = newAccount.name.split(' ',2);
                c.FirstName = names[0];
                c.LastName = names[1];
            }                        
            contactList.add(c);
        }
        
        
    }
    insert contactList;
    
    
    
}  

Answer 1

The query on Account can be moved out easily using the whole newAccountList as WHERE clause.
Then a Set is needed to store every "free" phone number.
At first it should be filled with every phone number from the accounts, so it can be used to retrieve all Contacts at once, then the contacts' phone must be removed from the Set.
Done that, the Set will hold only the needed phone numbers, so you can loop on accounts and, only if the phone number is in the set, create the related contact.
This way there will be no query inside loops.

public static void contactFromAccount(List<Account> newAccountList) {
    Set<String> phones = new Set<String>();
    List<Account> accounts = [SELECT Id, Name, Phone FROM Account WHERE Id IN :newAccountList];

    for (Account acc : accounts) {
        phones.add(acc.Phone);
    }
    phones.remove(null); // we don't need to retrieve Contact without phone as we need to skip accounts without phone
    
    for (Contact c : [SELECT Phone FROM Contact WHERE Phone IN :phones]) {
        phones.remove(c.Phone);
    }
    
    // Now phones contains only phone number that are related to no contacts
    List<Contact> contactToInsert = new List<Contact>();
    for (Account acc : accounts) {
        if (phone.contains(acc.Phone)) {
            Contact c = new Contact();
            c.AccountId = acc.Id;
            c.Phone = acc.Phone;
            if (acc.Name.contains(' ')) {
                List<String> names = acc.Name.split(' ', 2);
                c.FirstName = names[0];
                c.LastName = names[1];
            } else {
                c.LastName = acc.Name;
            }
            contactToInsert.add(c);
            // enable the next line to create at most one contact for each Phone
            // phone.remove(acc.Phone);
        }
    }
    insert contactToInsert;
}